Hi Suren On 2026/8/15 14:51, Suren Baghdasaryan wrote: > On Thu, Aug 13, 2026 at 2:34 AM Hao Ge <[email protected]> wrote: >> >> shutdown_mem_profiling() calls remove_proc_entry() from >> reserve_module_tags(), which runs under mod_lock held for write. >> remove_proc_entry() waits for readers, and a reader takes mod_lock for >> read in allocinfo_start(): >> >> CPU0 (insmod) CPU1 (read /proc/allocinfo) >> ---------------- ---------------------------- >> reserve_module_tags() >> down_write(&mod_lock) [held] >> use_pde() [in_use++] >> allocinfo_start() >> down_read(&mod_lock) <- blocks >> shutdown_mem_profiling() >> remove_proc_entry() >> wait for in_use == 0 <- blocks > > Yes, this is indeed a possible race. > >> >> Move remove_proc_entry() to a workqueue. >> >> Fixes: 4835f747d3ed ("alloc_tag: support for page allocation tag >> compression") > > I think all these issues were reported by Sashiko, so you should add a > Reported-by tag. >
Right, I'll add them. Patches 1 and 3 will be resent as a standalone two-patch series with the Reported-by tags included. Thanks a lot for all the help on this series. Thanks Best Regards Hao >> Signed-off-by: Hao Ge <[email protected]> > > LGTM > >> --- >> mm/alloc_tag.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c >> index 7481180dadd2..b80f5a151f28 100644 >> --- a/mm/alloc_tag.c >> +++ b/mm/alloc_tag.c >> @@ -591,6 +591,13 @@ void pgalloc_tag_swap(struct folio *new, struct folio >> *old) >> put_page_tag_ref(handle_new); >> } >> >> +static void remove_allocinfo_file(struct work_struct *work) >> +{ >> + remove_proc_entry(ALLOCINFO_FILE_NAME, NULL); >> +} >> + >> +static DECLARE_WORK(remove_allocinfo_work, remove_allocinfo_file); >> + >> static void shutdown_mem_profiling(bool remove_file) >> { >> if (mem_alloc_profiling_enabled()) >> @@ -600,7 +607,7 @@ static void shutdown_mem_profiling(bool remove_file) >> return; >> >> if (remove_file) >> - remove_proc_entry(ALLOCINFO_FILE_NAME, NULL); >> + schedule_work(&remove_allocinfo_work); >> mem_profiling_support = false; >> } >> >> -- >> 2.25.1 >>
